Needlebar mechanism for sewing machines



Dec. 4, w45.v

L. M, BALLAMY ET ALJ y mation.

Patented Dec. 4, 19.45

NEEDLEBAR MECHANISM Fon SEWING MACHINES Leslie Mark Ballamy, Caterham-on-Hill, and

Richard Hasell Sheepshanks, Eyke, Woodbridge, England Application May 11, 1942, Serial No. 442,575 In Great Britain July 11, 1941 3 ciaims. (o1. i12- 221) jdevice, which, in addition to bringing about the :reciprocation of the needlebar, also causes the `needle-holder to oscillate in afore and aft direction (i. e. in the directionof therow of stitches), thus compensating for the feeding movement of 'the material which is being sewn and enabling said material to be fed at a substantially steady rate.v

Y `It `is the object ofthe present invention to provide an improved form of mechanism, which is simple in construction and which enables the I needlebar itself to be carried in pivotal bearings instead of the usual sleeve of non-circular crosssection within which the needlebar is mounted for rectilinear sliding movement.

` In needlebar mechanism for a sewing machine,

comprising a needlebar, a crank or equivalent connected operatively with that end thereof remote from the needle-holder, and guiding means 'for theneedle-holder end of the needlebar, the

npresent invention is characterised by the fact thatsaid guiding means comprises a link device which is pivotally connected at spaced points, to the needlebar and toa locating member, respec- I tively, so that the needle-holder is caused to move in a. fore and aft direction as the needlebar as a whole reciprocates.

l Further there is provided 4in accordance with the invention needlebar mechanism for a sewing `machine, comprising a needlebar, a crank or Fequivalent connected operatively with that end thereof remote from the needle-holder, and guiding means for the needle-holder end of the needlebar, characterised by the fact that the l guiding means comprises a link device connecting `the `needlebar with a locating member, which latter is caused to change its position as the needlebar reciprocates, thus regulating the movement of the needle-holder in a fore and aft di- ,Asafurther feature of the invention Yneedlebar mechanism for a sewing machine 'is provided comprising in combination a needlebar provided with a needle-holder at one end, means at the opposite end `for reciprocating said needlebar, a locating member, means for regulating the position `of the locating member so that it occupies a predetermined position for each point in the cycle of reciprocation of the needlebar, and a link device connecting the needlebar with the locating member so as to impart a predetermined movement in a fore and aft direction to the needleholder.

If desired the means, such as a rotating cam, for moving the locating member may be driven from, or in common with the needlebar, and the locating member may comprise a plunger which is mounted for sliding movement in a housing secured to the body of the machine. Where a cam is used for moving the locating member, said locating member may be urged into engagement with said cam by means of a spring, the latter conveniently being disposed within the plunger and being arranged to act between a surface upon the interior of the plunger, and lan abutment block which is also disposed within the plunger and is anchored to the housing by means of a pin passing through a slot in the plunger. The needlebar is preferably connected with the locating member by a pair of links disposed one on each side of the needlebar, while the latter may be formed in two parts which are secured together by a device arranged to give way should the force in the needlebar exceed a predetermined value. Thus a sleeve carried by one part of the needlebar may t telescopically over the other part, said Sleeve being connected to said other part by a transverse pin adapted to shear in the event of the needlebar being overloaded The invention is illustrated by Way of example in the accompanying drawing, in which:

Figure 1 is a side elevation of the needlebar with its mounting and driving mechanism, cer-- tain parts being shown in section; and

Figure 2 is a sectional plan taken on the line 2-2 of Figure 1.

The needlebar, which is indicated generally at I0, is formed at its lowerend with a needleholder II adapted to grip a single needle, or a set of needles where a plurality of mutually parallel rowsV of stitching are to be made simultaneously.` The lower part I2 of the needlebar I0 is of rectangular cross-section, as will be seen in Figure 2, and it is secured at its upper end to a sleeve I3 which lits slidably over a rod I4, said sleeve being secured to the rod I4 by means of a transverse pin I5, which is sufficiently soit and small in cross-section to shear if the compression (or tension) in the needlebar I0 should exceed a predetermined safe value. The rod I4 is screwthreaded at I6 for engagement with an adjusting member I1, a lock nut I8 being provided. The upper part of the adjusting member I1 is screwed with a spigot I9 having a screw-thread which is of opposite hand to the thread I6 and/or is of fat-equal speeds. .cam 38, the shape of which will be seen more .clearly in Figure yl, said cam being arranged to A block 21 is secured tothe portion I2 ofthe needlebar and carries a transverse pin 28 serving as the pivotal mounting for one end of each of a pair of links 29 and 30. "The opposite ends of these links are connected together by a pin 3|, which is freely rotatable within a `'locating member constituted by a transverse bush v32 formed upon the extremity of a tubular plunger 33. This plunger is horizontally slidable withina-housing 34, which is secured to a convenient fixed part'ofthesewing machine, and which .is

provided with a pair of arms 35 and 36 suitably tted with bearings'for a driving shaft 31. The

`latter is driven from, or in common with, the

crank shaft 25, so lthatthe two shafts rotate The shaft 3l is fitted Witha be engaged by a follower roller 39 pivotally 'rnounted-upon the Vadjacent end of the plunger 33 by means-of a transverse pin 40. In order to maintain the roller 39 in contact with the pefriphery of the cam 38, said plunger 33 contains fa 'coiled compression spring 4I, which at one end, bears against the `end interior surface .42 of the plunger, while its opposite extremity engages with Aan abutment block 43, which is anchored with 'respect to the housing-34 by means of a transverse pin 44. A.pair of diametricallyopposed slots 45 `formed in the plunger 33 permitthe vrequisite axial movement lof said plunger, and lat the same time prevent rotation thereof re1- /ative to the housing 34 owing to the restraining Vaction of the transverse pin 44. also keeps the bush 32Ytruly parallel with the pin `28 in the block 2'! and thus avoids ythe'creation .offunnecessary friction inthe mounting of the This, of course,

links 29 and 30. To the under side ofthe housing 34 a bearing bracket-45 is secured and serves as the pivotal attachment for a lever 41 carrying `lapresser foot 48 atits extremity, the opposite en'd of said lever 4l being connected with the housing 34 by means of a coiled tension spring 49 in order `to createthe necessary downward pressure upon the presser foot 48. vThe usual form of mechanism (not shown) in order to vsecure a proper stitching action.

The needlebarmechan-ism whichis illustrated 'orneedles lllA to move'forvvards (i. e..to theright) Awhile it or 'they `'are penetrating the material 'which is being sewn, saidneedle or needles being sequence. Y desirable that the .material to ybesewn should vshaping the cam 38. Thus as the needlebar I0 descends, the locating member constituted by the plunger 33 and bush 32 has its position so regulated from instant to instant that the needle Y Vor needles v5I `d`o 4not drag the material as the latter is penetrated by the needle or needles.

TheV invention ais primarily intended for use in machines where a number of needlebars are arranged to operate side by side so as to produce numerous parallel rows of stitching in sheet material, such as quilting, composed of .kapok or other fibrous substances. The -various Aneedlebars in such Va machine are usually drivenby -a-common crank shaft, such asi25, but are arranged in various phases soethat theyexecute their penetrating strokes in a predetermined With such machines it isv particularly be fed steadilypast the needles, -and the improved arrangement achieves `this result. The `invention is, however,` equally applicableto sewying machines in which a single needlebar is used.

It will be appreciated that the arrangement described is given merely as an example and vremote from the needle, and alink pivoted at -one end to theneedle bar vadjacent the needle and extending laterally from said needle bar, a

' locatingmember, the opposite-end of .said link being pivotally connected tothel locating member,

said crank and said `link forming theisole supporting and locating meansfor the-needle bar.

2. Needle bar mechanism-for a sewingimachine, comprising a rigid 'needlerban meansatoneend ofsaidbar to receive'a need1e,a continuously rotatable crankshaft, a cranky onfsaid shaft, Esaid crank pivotally carrying that'end of the needle `bar remote from the needle, alocatingrmember, .a cam driven in commonwithfthe crankshaft andY operative tofmovethe flocatin'g .member inva direction `laterallyuof theneedle bar, and a link pivotally `connected ati Aone en'd tot the I needle bar at a position adjacenttheineedle,said.linkextending laterally fromfsaidi'needlet bar zand; pivotally connectedat theiend remote fromthevneedle 'bar `'to the `locating member, v the.- saidr crankfarid the link `forming fthe/sole suppo-rtinglan'dflocating means for` the needle bar.

3. A construction as defined in claim 2 wherein Vthe locating means Yis n.guided 'rectilinear-ly, and

wherein a springurgesithefsaid locatingltmeans 'into engagement withfthecam.`

AT EISLIE 'MRKJBALILAMY. I

RICHARD HASELLSHEEPSH'ANKS. Y 

